Now we got two pictures of simular instruments here - the second one added by me today. The painting is by Fra Angelico, and it's from about 1440. The instrument has three single strings, but looks very much like a mandolin. The right hand technique looks interesting as well. Any comments?
This instrument is most likely a gittern which is described as a short necked, round backed, lute with a sickle shaped pegbox by Lawrence Wright in The Medieval Gittern and Citole: A case of mistaken identity. Another more accessible article can be found here: http://www.diabolus.org/guide/gittern.htm
Yes, you are probably right, about that, Mike. The only confusing part is that it has three single strings, while the gittern around 1450 had 5 courses (according to the text). But there were sure differnt models of the instrument...